Flat, flexible footwear sold by Mequon, WI-based Dr. Comfort is associated with significant reductions in knee adduction moment (KAM) in patients with knee osteoarthritis (OA), according to a small proof-of-principle study e-published on April 23 by Arthritis & Rheumatism.

In addition, after six months of wearing the experimental shoe, participants were able to sustain a KAM reduction even when they shed their mobility shoes, according to the study.

Two of the authors, Najia Shakoor, MD, and Roy Lidtke, DPM, both from Rush University Medical Center in Chicago, invented the study shoe, which has a series of grooves on the sole at major flexion points to mimic barefoot-like foot movement and is sold under Dr. Comfort’s Flex-OA line.

In the current study researchers compared KAM, a surrogate measure of knee loading, in 16 people with moderate-to-severe medial compartment knee OA who underwent gait testing in their own shoes (a pair usually used for walking), barefoot, and in the mobility shoes at baseline and six, 12, and 24 weeks. After baseline testing, participants wore the mobility shoes at least six hours a day, six days a week, for the duration of the study.

Compared with baseline measures in their own shoes, participants had an 18% reduction in KAM with the mobility shoes at 24 weeks. Researchers found no significant difference in KAM between walking with mobility shoes and walking while barefoot.

Participants also had KAM reductions from baseline of 11% and 10% while walking in their own shoes and barefoot, respectively, compared with baseline, which the authors said suggests the mobility shoes can “retrain” gait so wearers retain beneficial alterations.

Findings need to be confirmed by larger, longer trials with a blinded control group, authors noted.